Generally, an artificial joint is formed of an acetabular portion and a femur portion. The above femur portion includes a ball engaged with the acetabular portion, a stem inserted into a human's femur and a neck for connecting the stem and the ball. Here, the acetabular portion is formed of an abrasion resistance material like a polyethylene. The femur portion is formed of a certain material like a metal or ceramic. However, the acetabular portion and the femur portion may be made of the same ceramic material.
In a joint operation, when an artificial joint which is formed of the above material and has the above structure is engaged with a human's femur having a cortical bone or a porous bone and a bone cavity therein, since the stem of the artificial joint must be properly engaged with the femur, the femur must have a longitudinal femoral canal cavity therein of which the diameter and length correspond to those of the engaged stem. The operation in which the stem of the artificial joint is engaged to the femur will be described in detail.
FIGS. 1A through 1F are views for describing a manual operation of the hip joint operation.
When a reamer 20 is stated to inserted into the femur 10 engaged with a hip joint, as shown in FIG. 1A, and is inserted by a certain depth in a longitudinal direction of the femur 10, as shown in FIG. 1B, and is removed from the femur 10, as shown in FIG. 1C, a reamer insertion femoral canal cavity 12 is formed in the femur 10.
Next, as shown in FIGS. 1D through 1E, when a broach 30 having the same shape as that of an artificial joint is inserted into the reamer insertion femoral canal cavity 12, the femur 10 is excavated or formed in the same shape as the broach 30. Here, in the drawing, reference numeral 14 represents a bone removing portion formed in the femur 10 by the broach 30.
At this time, it is impossible to accurately form a femoral canal cavity in the femur by a manual operation in order for the position and size of the same to be accurately matched with those of the artificial joint. Therefore, when the artificial joint operation is manually performed, the artificial joint may not be properly or accurately engaged with the femur.
In order to improve the above problems which occur due to the manual work in which the artificial joint is engaged to the femur, a femur is machined using an operation robot. The femur operating by the robot will be described in detail with reference to the accompanying drawings.
FIG. 2 is a view illustrating a prior art robot operation system which includes an operating table 100, an operation robot 120 fixedly installed in an operating room or operating table for thereby performing an operation of a patient 110, and a computer 130 connected with the operation robot 120 for controlling an operation performed by the operation robot 120. Here, in the drawings, dotted line 140 represents a work space in which the operation robot 120 works during the operation.
In the above robot operation system, since it is possible to accurately process the shape of the femoral canal cavity to match with the shape of the artificial joint compared to the operation in which the femoral canal cavity is processed by a manual method, it is possible to accurately engage the artificial joint to the femoral canal cavity.
However, since the prior art robot operation system has a big volume and is fixedly installed in a floor of the operating room or the operating table, it cannot be moved one place to another. In addition, as indicated by the dotted line of FIG. 2, the prior art operation system has a large workspace. Also, the prior art robot system needs an additional system for detecting a position of a corresponding bone before the operation and an apparatus for preventing the femur from being moved during the operation, thereby the prior art robot operation system is expensive and is not widely used.